Hi.
First of all, thanks for such a great machine Sandy!
Now my problem.
I have Arduino Mega with Adafruit. Motors are working almost right but when they are still left one is tense (it "holds" the cord and it is hard to pull cord by hand) and the second one is loose (i can easily pull cord, there is no holding torque).
Any suggestions will be great:)

I realize this is an old thread, but was up early and looking for things to do. So, perhaps my comment will help someone in the future with similar issues.

Another potential failure for steppers is overheating, which can permanently damage the magnets. If your motor was purchased used, you don't know what situation it came from. It may have been given higher voltage than it should have. Another totally different possibility, is that the motor controller is not providing the current or voltage you need.

-Joe Dunfee